Sosefina Amoa came to the United States this month and joined a convent in the District with an eye toward studying to become a nun.

She didn’t know she was pregnant.

So when she delivered a baby boy alone on the floor of her room with the Little Sisters of the Poor last week, police said the 26-year-old Samoan woman panicked and put a cloth over the infant’s mouth and nose, suffocating the boy minutes after he was born.

The disturbing details were laid out in an affidavit filed by D.C. police in support of a warrant charging her with first-degree murder in the child’s death.

The court papers said that on Oct. 10, leaning on her bed for support, Ms. Amoa birthed the child onto the floor. She named him Joseph, and she laid with him for a time.

But after giving birth, “she didn’t know what to do and was afraid that someone would hear the child crying and learn of her pregnancy.” So Ms. Amoa pressed a wool garment over his face until he stopped breathing.

According to the court documents, Ms. Amoa appeared not to have realized she was pregnant and told investigators that when she experienced bleeding the day before she gave birth she thought it was her menstrual cycle.

The day after giving birth and cleaning the room, Ms. Amoa summoned a nun and presented the dead baby.

The nun placed the infant, who was cold and stiff, inside a small black luggage bag and both he and Ms. Amoa were taken to Providence Hospital, located blocks from the 7-acre campus where the convent is located.

When investigators went to Ms. Amoa’s room, they found bloody cloths used to clean the room as well as placenta and a portion of an umbilical cord stuffed into a trash pail. The young woman told detectives she had thought to put the body of the 6-pound newborn in the trash as well but later decided “that was a wrong thing to do,” court documents state.

The documents indicate the woman initially told the nun she had found the baby’s body outside but later changed her story and admitted that she was the mother.

She was initially expected to make her first appearance in D.C. Superior Court on Thursday, but instead was hospitalized. The reason for her hospitalization was unclear.

The U.S. Marshals Service said Ms. Amoa was in the central cell block when she was transported to a hospital around 11:30 a.m. U.S. Marshals spokesman Deputy David Neumann said she did not appear to have injuries but that he could not divulge the reason for her hospitalization due to privacy concerns.

A judge set a $200,000 cash bond in the interim, said William Miller, spokesman for the U.S. Attorney’s Office for the District.

The Public Defenders Service was listed as representing Ms. Amoa but no one could be reached for comment on her case or condition.

According to the arrest warrant filed in D.C. Superior Court, Ms. Amoa was training as a postulant at the convent but told police she had not disclosed her prior sexual encounters to the organization.

A representative from the Little Sisters of the Poor, which operates an elderly care facility in the 4200 block of Harewood Road in Northeast, declined to speak about Ms. Amoa’s relationship with the order. Court records state that she arrived there on Oct. 5 after traveling from her home in Samoa.

“All I can say is it’s a really tragic situation, and we’re all praying for everyone involved,” said Sister Constance when reached by phone.

Little Sisters of the Poor is a Roman Catholic women’s organization founded in 1839 that operates care facilities across the globe, including in Samoa.